CTL_STATUS_t sensecore_get_tx_signal(SENSECORE_DRIVER_t *self, int site);
sensecore_get_tx_signal reads the Tx signal for the SenseCore self on site site. The port pin associated with the Tx signal is set to input mode before reading.
sensecore_get_tx_signal returns an extended status code: 0 if the Tx signal is low, 1 if the Tx signal is high, and a negative value indicating an error.
sensecore_get_tx_signal is thread-safe if the transport member in self is thread-safe. This requires that a mutex is associated with the I2C bus provided when initializing self.